The PicoJet Combat is indeed made of some form of Europeon ARCEL knockoff. This foam is less rigid but more durable than stryofoam and more rigid but less durable than EPP.

ARCEL is a competitor to EPP in the packaging material market for extremely sensitive electronic components.

The main advantage of ARCEL is that it is injection moldable. True EPP cannot be molded for model airplane applications because it undergoes 24 hours of uncontrolled expansion when removed from the mold.

Aluminum tooling for an ARCEL plane is ~$20,000 to $50,000 depending on the number of cavities and complexity.

Tooling for an EPP plane is ~$250 to $300 if you build it yourself. All necessary parts are available at Lowes, Menards, or Home Depot, plus a smattering of screws and washers from Micro Fasteners.